IMG News

IMG Seminar 14th April 2010

2010-04-08T10:37:00.001Z

Title: Sybil Resistant - Authentication in Mobile Ad-hoc Networks

Presenter: Sarosh Hashmi

Venue: 13.00 14th April 2010 in 1.3, Kilburn Building

Abstrtact:
Generating and verifying identities of nodes in an open Mobile Ad-hoc Network (MANET) is a challenging task. In the absence of any Trusted Third Party (TTP), nodes can acquire multiple identities and can misuse them to launch Sybil attack. In this attack, multiple identities can be employed by a malicious node to disrupt network operation or acquire disproportionate share of network resources. To cope with Sybil attack, we propose to use the hardware id of the devices carried by nodes as their identity. A mechanism is devised that enables the nodes verify hardware id of each other with minimal input from the TTP. In this scheme, an authentication agent is assigned the task of verifying the hardware id of authenticatee node. The task of the TTP is to sign the authentication agent in order to provide assurance that it does not perform any harmful tasks at the visiting host. Moreover, we have carried out a detailed analysis of various static and dynamic attacks that may be launched by a potential malicious host against the authentication agent. Consequently a model is devised to protect the agent from such attacks. This model results in increase security of authentication agent and reduces the avenues for a potential malicious host to acquire multiple identities for launching Sybil attack.

IMG Seminar 17th March 2010

2010-03-11T10:36:00.002Z

Title: Adaptive Join Processing in Pipelined Plans

Presenter: Norman Paton

Venue: 13.00 17th March 2010 in 1.3, Kilburn Building

Abstrtact:
In adaptive query processing, the way in which a query is evaluated is changed in the light of feedback obtained from the environment during query evaluation. Such feedback may, for example, establish that misleading selectivity estimates were used when the query was compiled, leading to the optimizer choosing an inappropriate join order or unsuitable join algorithms. This paper describes how joins can be reordered, and the join algorithms used replaced, while they are being evaluated in pipelined plans. Where joins are reordered and/or replaced during their evaluation, the approach avoids duplicating work that has already been carried out, by resuming from where the previous plan left off. The approach has been evaluated empirically, and shown to be effective for improving query performance in the light of misleading selectivity estimates.

IMG Seminar 10th March 2010

2010-03-03T07:20:00.002Z

Title: Feedback-Based Annotation, Selection and Refinement of Schema Mappings for Dataspaces

Presenter: Khalid Belhajjame

Venue: 13.00 10th March 2010 in 1.3, Kilburn Building

Abstrtact:
The specification of schema mappings has proved to be time and resource consuming, and has been recognized as a critical bottleneck to the large scale deployment of data integration systems. In an attempt to address this issue, dataspaces have been proposed as a data management abstraction that aims to reduce the up-front cost required to set-up a data integration system by gradually specifying schema mappings through interaction with end users in a pay-as-you-go fashion. As a step in this direction, we explore an approach for incrementally annotating schema mappings using feedback obtained from end users. In doing so, we do not expect users to examine mapping specifications; rather, they comment on results to queries evaluated using the mappings. Using annotations computed on the basis of user feedback, we present a method for selecting from the set of candidate mappings, those to be used for query evaluation considering user requirements in terms of precision and recall. In doing so, we cast mapping selection as an optimization problem. Mapping annotations may reveal that the quality of schema mappings is poor. We also show how feedback can be used to support the derivation of better quality mappings from existing mappings through refinement. An evolutionary algorithm is used to efficiently and effectively explore the large space of mappings that can be obtained through refinement. The results of evaluation exercises show the effectiveness of our solution for annotating, selecting and refining schema mappings.

SNEE: Sensor Network Query Compiler/Optimizer :: Source Code Release

2009-12-14T16:36:00.003Z

Project page: http://snee.cs.manchester.ac.uk/

We would like to announce the release of the SNEE sensor network query compiler/optimizer. SNEE (for Sensor NEtwork Engine) has been developed at the University of Manchester. It supports an expressive continuous, declarative query language over acquisitional streams, called SNEEql, using a software architecture that extends traditional distributed query processing techniques.

SNEEql queries are compiled into query evaluation plans (QEPs) in the form of executable nesC/TinyOS code. SNEEql QEPs currently target the TOSSIM simulator and the Avrora Mica2/MicaZ instruction-level
simulator (TinyOS 1.x only). We have also run SNEE-generated QEPs on Tmote Sky motes running TinyOS 2.x, and a further release in which the generated QEPs are fit for small-scale experiments on such mote-level
hardware is planned for the next few months.

The SNEE compilation/optimization architecture explicitly makes a broad range of query planning decisions that take into account the resource constrained nature of sensor networks, including:

routing (i.e., determining the paths along which result tuples should travel),
fragmentation (i.e., deciding where to evaluate different portions of the plan), and
timing (i.e. identifying when to perform computations and communications in order to meet user-specified quality-of-service (QoS) expectations).

The versatility in the generation of QEPs enables the distribution of different fragments to nodes within the sensor network (thereby enabling the in-network evaluation of fairly complex queries, and hence, potentially reaping the energy savings associated with that approach to a greater degree than in comparable systems).

SNEE compilation/optimization is also responsive to explicitly-stated QoS expectations, such as delivery time. A version of SNEE is being prepared that will enable multiple query evaluation as well as responsiveness to a broader range of QoS expectations than are currently supported by any comparable sensor network query processing software.

SNEE was first developed in the DIAS-MC project funded by the UK EPSRC and is currently being significantly further developed and deployed in the SemSorGrid4Env project ( http://www.semsorgrid4env.eu/ ) funded by
the European Union.

SemSorGrid4Env aims to provide enabling technology for the semantic discovery and integration of diverse sensor networks (and other data resources such as historical databases or satellite imagery) to support the development of on-the-fly data mashups involving streaming sensor data in the context of disaster response scenarios. One of the prototypes being developed as a demonstrator for this project is a fire-prevention application, and plans are underway to deploy SNEE in a sensor network for monitoring the risk of forest fires in Spain.

The source code of SNEE has been released under the New BSD License, and is hosted at:

http://code.google.com/p/snee/

At the above URL, you can download the source, with some simple examples. The quickest way to get up and running is to follow the 'getting started guide' link in the above page.

The following associated publications are currently available:

Overview paper:

- Comprehensive Optimization of Declarative Sensor Network Queries.
Ixent Galpin, Christian Y. A. Brenninkmeijer, Farhana Jabeen, Alvaro A. A. Fernandes, and Norman W. Paton.
In SSDBM, pages 339-360, 2009.

http://dblp.uni-trier.de/rec/bibtex/conf/ssdbm/GalpinBJFP09.xml
Available at: http://snee.cs.manchester.ac.uk/ssdbm09.pdf

Other papers about SNEE:

- Validated Cost Models for Sensor Network Queries.
Christian Y. A. Brenninkmeijer, Ixent Galpin, Alvaro A. A. Fernandes, and Norman W. Paton.
In DMSN, (Article no. 8), 2009.

http://dblp.uni-trier.de/rec/bibtex/conf/dmsn/BrenninkmeijerGFP09.xml
Available at: http://snee.cs.manchester.ac.uk/dmsn09.pdf

- A Semantics for a Query Language over Sensors, Streams and Relations.
Christian Y. A. Brenninkmeijer, Ixent Galpin, Alvaro A. A. Fernandes, and Norman W. Paton.
In BNCOD, pages 87-99, 2008.

http://dblp.uni-trier.de/rec/bibtex/conf/bncod/BrenninkmeijerGFP07.xml
Available at: http://snee.cs.manchester.ac.uk/bncod08.pdf

- An Architecture for Query Optimization in Sensor Networks.
Ixent Galpin, Christian Y. A. Brenninkmeijer, Farhana Jabeen, Alvaro A. A. Fernandes, and Norman W. Paton.
In ICDE, pages 1439-1441, 2008.

http://dblp.uni-trier.de/rec/bibtex/conf/icde/GalpinBJFP08.xml
Available at: http://snee.cs.manchester.ac.uk/icde08.pdf

More information is available at our project page:

http://snee.cs.manchester.ac.uk/

We would be very grateful for any comments or questions, so do let us know your experiences, good or bad, if you try out the software. For this purpose, and as default for projects hosted by Google Code, the SNEE page ( http://code.google.com/p/snee ) comes with a Wiki as well It as Group Discussion fora. If you prefer to email us directly, please use {ixent,alvaro}(at)cs.man.ac.uk .

External links to software/hardware platforms mentioned above:

nesC/TinyOS http://docs.tinyos.net/index.php/Main_Page
TOSSIM http://www.eecs.berkeley.edu/~pal/research/tossim.html
http://docs.tinyos.net/index.php/TOSSIM
Avrora http://compilers.cs.ucla.edu/avrora/
Mica2 http://www.xbow.com/Products/productdetails.aspx?sid=174
MicaZ http://www.xbow.com/Products/productdetails.aspx?sid=164
Tmote Sky http://www.sentilla.com/moteiv-transition.html

Three papers from IMG members accepted at the EDBT 2010 conference

2009-12-10T13:17:00.001Z

EDBT ("Extending Database Technology") is one of the top conferences in the broad area of data management. We are happy to announce that this year's edition will feature three papers from IMG people, and they are:

Khalid Belhajjame, Norman W. Paton, Suzanne Embury, Alvaro A. A. Fernandes and Cornelia Hedeler. Feedback-Based Annotation, Selection and Refinement of Schema Mappings for Dataspaces

Paolo Missier, Norman Paton and Khalid Belhajjame. Fine-grained and efficient lineage querying of collection-based workflow provenance

Kwanchai Eurviriyankul, Norman W. Paton, Alvaro A. A. Fernandes and Steven Lynden. Adaptive Join Processing in Pipelined Plans

Congratulations especially to Norman, who is a co-author of all three!

Web Accessibility Expert Interviewed By Spanish Media

2009-12-08T12:02:00.000Z

A local Spanish media, NoticiasdeGipuzkoa.com, recently featured an interview with Dr. Simon Harper on Web accessibility and how it will give blind users the independence to purchase online. He discussed about the aspects of making a website accessible, the benefits of doing it, and the practicability of achieving it.

Read the original full article at http://www.noticiasdegipuzkoa.com/2009/12/02/sociedad/euskadi/una-web-accesible-permite-a-un-usuario-ciego-comprar-online-y-asi-ganar-autonomia. For the translated English version of the article click here.

Full paper accepted to the Computers in Human Behavior

2009-12-04T14:45:00.003Z

A full paper titled, "Small Device Users Situationally Impaired by Input" by Yeliz Yesilada, Simon Harper, Tianyi Chen and Shari Trewin has been accepted to the prestigious Computers in Human Behavior Journal. This paper is written as part of the collaboration between the HCW researchers and Shari Trewin from IBM Watson Research Center.

This paper describes empirical work which makes the link between the behaviour of motor impaired desktop users and non--impaired users of small--devices. This is important because it may, therefore, be possible to leverage existing solutions for motor impaired users into the small--device domain. We find that there is significant overlap in the extent of the problems encountered, but not the magnitude. Eight of the eleven existing errors made by motor impaired users were also present in our small--device study in which two additional error types, key ambiguity and landing errors, were also observed. In addition, small--device rates for common error types were higher than those of desktop users with no impairment, but lower than those of desktop users with motor impairments.

2009-11-02T16:41:00.003Z

Taverna 2 formal semantics paper accepted for publication

Our paper on the formal semantics of Taverna 2 has been accepted for publication in the Special Issue on Scientific Workflows of the Journal of Computer and System Sciences.

This is good news: the paper is a result of an ongoing collaboration between the myGrid people, Jan Hidders of the Technical University of Delft, NL, and Jacek Sroka, of the University of Warsaw, Poland.

Here is the temporary citation:

Jacek Sroka, Jan Hidders, Paolo Missier, and Carole Goble, Formal semantics for the Taverna 2 Workﬂow Model, Journal of Computer and System Sciences, Special Issue on Scientific Workflows, 2010, in press.

This is a relevant paper, in that it provides a formal foundation for the new version of the Taverna workflow management system. A similar "formal semantics" paper, which however follows a different modelling approach, described the original Taverna model and appears in the procs. of the IEEE e-science conference: DOI.

ISWC 2009 Best Poster Award

2009-10-29T20:20:00.006Z

Congratulations to Matthew Horridge, Bijan Parsia and Uli Sattler, who won the "Best Poster & Demonstration Award" at the 8th International Semantic Web Conference for their joint poster "Understanding Justifications for Entailments in OWL". More information is available at the ISWC 2009 posters & demos page and in the related OWLED paper (PDF).

OWL 2 is now a recommendation!

2009-10-28T12:58:00.004Z

Two years ago, the W3C started a working group to standardize the next generation of the Web Ontology Language (OWL). On Tuesday, OWL 2 was completed.

Professor Uli Sattler and Bijan Parsia of the IMG were significant participants in the working group. The main changes to the logical underpinnings of OWL are based on Sattler's research into the Description Logic SROIQ and Parsia was a co-editor of the Primer, the Structural Specification, and the XML Serialization.

OWL 2 is based on the OWL 1.1 member submission to the W3C. OWL 1.1 was developed in the OWL: Experiences and Directions (OWLED) workshop series (which was co-founded by Parsia).

The OWL working group also produced a "W3C note" describing the "Manchester Syntax" developed by Matthew Horridge.

Software developed by the University of Manchester (in both the IMG and the BHIG), including Protégége 4, FaCT++, and the OWL API played a key role in the standardization process. Significant features of OWL 2 were developed in response to application and user insight from Robert Stevens, Alan Rector, and the rest of the BHIG.

Further reading:

The Manchester OWL page

OWL 2: The next step for OWL

The University of Manchester press release

The W3C press release and testimonials

IMG Seminar 11th November 2009

2009-10-26T17:07:00.001Z

Title: Project Wonderland

Presenter: Bernard Horan, Sun Microsystems

Venue: 13.00 11th November 2009 in 1.3, Kilburn Building

Abstract:
Project Wonderland is an open-source toolkit for building 3D virtual worlds. The platform supports immersive audio, 2D and 3D shared applications, multi-user Java programs in 2D or 3D, and telephony integration. The environment, built on the Project Darkstar game server infrastructure, is open and extensible, allowing developers to create highly customized virtual worlds of all different types. Bernard will provide a description of Project Wonderland's features and show several different virtual worlds built by members of the Project Wonderland open source community. Each world highlights different aspects of the Wonderland platform and the wide range of possibilities open to developers.

Full paper accepted to the International Journal of Human-Computer Studies

2009-10-22T14:10:00.000Z

The researchers from the HCW lab had a journal paper accepted to the International Journal of Human-Computer Studies. The journal covers interdisciplinary research in computing, artificial intelligence, psychology, linguistics, communication, design, engineering, and social organisation.

The paper, titled "What Input Error Do You Experience? Typing and Pointing Errors of Mobile Web Users", is written by Tianyi Chen, Dr. Yeliz Yesilada and Dr. Simon Harper. The paper presents a user study that
investigates the input errors of mobile Web users in both typing and pointing. The study identifies six types of typing errors and three types of pointing errors shared between motor-impaired desktop users
and mobile Web users. Results show that mobile Web users often confuse the different characters located on the same key, press keys that are adjacent to the target key, and miss certain key presses. When using a stylus, they also click in the wrong places, slide the stylus during multiple clicks, and make errors when dragging. Those results confirm that despite using different input devices, mobile Web users share common problems with motor-impaired desktop users; and it would be beneficial to transfer available solutions between these user domains in order to address their common problems. This work is part of the RIAM project funded by EPSRC (EP/E002218/1).

Accessibility = Flexibility

2009-10-01T11:04:00.002Z

In a recent blog post at Fluid Blog, Dr. Simon Harper discusses why creating accessible Web pages also means making them future proof against changes in guidelines, recommendations, and design. To read more about
Accessibility = Flexibility please visit http://blog.fluidcreativity.co.uk/accessibility-flexibility/

IMG Seminar 23rd September 2009

2009-09-21T14:35:00.001Z

Title: The Complexity of Reasoning for Fragments of Default Logic

Presenter: Arne Meier, University of Hannover

Venue: 13.00 23rd September 2009 in Atlas 2, Kilburn Building

Abstract:
Default logic was introduced by Reiter in 1980. In 1992, Gottlob classified the complexity of the extension existence problem for propositional default logic as Sigma^P_2-complete, and the complexity of the credulous and skeptical reasoning problem as Sigma^P_2-complete, resp. Pi^P_2-complete. Additionally, he investigated restrictions on the default rules, i. e., semi-normal default rules. Selman made in 1992 a similar approach with disjunction-free and unary default rules. In this paper we systematically restrict the set of allowed propositional connectives. We give a complete complexity classification for all sets of Boolean functions in the meaning of Post's lattice for all three common decision problems for propositional default logic. We show that the complexity is a trichotomy (Sigma^P_2-, NP-complete, trivial) for the extension existence problem, whereas for the credulous and sceptical reasoning problem we get a finer classification down to NL-complete cases.

IMG Seminar 9th September 2009

2009-09-02T13:34:00.002Z

Title: Population-based data source completeness measurement

Presenter: Nurul Emran

Venue: 13.00 9th September 2009 in Atlas 1, Kilburn Building

Abstract:
Concerns surrounding data source selection based on the quality aspects have been motivated by the consequences of poor quality data experienced by people in everyday life. In particular, completeness of a data source is one of the quality aspects that becomes the important basis of data source selection's decision-making process. Our research is aimed at providing systematic data source selection based on its completeness. In the research, we explored the complexity of measuring data source completeness which calls for a model that can neatly capture user requirements on multi-dimensional completeness-oriented data source selection. In this talk, I will specifically explain about population-based data source completeness measurement (PSCM) model, which is proposed to fulfil the gap in the current studies of data quality.

Doctoral Consortium Paper Accepted at ASSETS'09

2009-08-26T14:16:00.002Z

A Doctoral Consortium paper by Alex Q. Chen, has been accepted at the 11th International ACM SIGACCESS Conference on Computers and Accessibility, Pittsburgh, PA, USA. The paper titled "Identifying Web Widgets for Accessible Web Content", summarizes the research project "Widget Identification and Modification for Web 2.0 Access Technologies (WIMWAT)". WIMWAT seeks to identify Web widgets from the Web page's source code, so that the methods employed by the widgets to dynamically update Web content can be evaluated for its accessibility. Through this approach, it is envisioned that widgets using methods that produces inaccessible content, can be modified into an accessible form during development. Thus, providing a conducive environment for Web developers/authors to develop Rich Internet Applications that delivers true accessible content.

The ASSETS 2009 Doctoral Consortium is funded by the US National Science Foundation.

W3C Publishes SKOS Recommendation

2009-08-19T09:07:00.009Z

From Chaos, Order: SKOS Recommendation Helps Organize Knowledge

The W3C today announced publication of the Simple Knowledge Organization System (SKOS) Recommendation. SKOS builds a bridge between the world of knowledge organization systems - including thesauri, classifications, subject headings, taxonomies, and folksonomies - and the linked data community, bringing benefits to both.

Sean Bechhofer of the Information Management Group was an editor of the Recommendation document. Other members of the IMG also provided valuable input to the process, including implementation experience.

Technical Paper Accepted at SIGDOC 2009 Indianapolis, USA

2009-08-10T11:19:00.000Z

A technical paper titled, “The Transition From Web Content Accessibility Guidelines 1.0 to 2.0: What This Means For Evaluation and Repair” by Grace Mbipom and Simon Harper has been accepted at SIGDOC 2009, Indianapolis, USA. The paper discusses the implications of the transition for automated evaluation and repair in particular. In addition, the authors motivate the need for the adoption of cross-disciplinary techniques for automated accessibility evaluation and repair of Web content.

IMG Seminar 12th August 2009

2009-07-30T13:01:00.001Z

Title: The Explicator Project: Integrating Astronomy Data with Semantic Web Tools

Presenter: Alasdair Gray

Venue: 13.00 12th August 2009 in Atlas 1, Kilburn Building

Abstract:
In this seminar I will report on the work conducted in the initial 18 months of the Explicator project which aims to use semantic web tools to integrate astronomy data. We addressed two of the key challenges when integrating data from multiple heterogeneous sources: (i) locating those data sources that contain data of interest, and (ii) understanding the data models in order to pose a query to extract the required data. For the first of these challenges, we investigated how to search for relevant source using SKOS encoded vocabularies and information retrieval techniques. For the second we investigated the use of RDB2RDF tools for exposing existing relational data sources.

Full Paper Accepted at ASSETS 2009 Pittsburgh

2009-07-23T11:44:00.001Z

The researchers from the HCW lab had a full technical paper accepted at ASSETS 2009. The ASSETS conference explores the use of computing and information technologies to help persons with disabilities and older adults. This year it will be held in Pittsburgh, USA.

This paper is part of a collaboration work between the UK EPSRC funded RIAM project (EP/E002218/1), and the University of Udine. This full technical paper "How Much Does Expertise Matter? A Barrier Walkthrough Study with Experts and Non-Experts" by Yeliz Yesilada, Giorgio Brajnik and Simon Harper, investigates the interplay between expert and non-expert evaluation by conducting a Barrier Walkthrough (BW) study with 19 expert and 51 non-expert judges. The BW method provides an evaluation framework that can be used to manually assess the accessibility of Web pages for different user groups including motor impaired, hearing impaired, low vision, cognitive impaired, etc. this paper concludes that the level of expertise is an important factor in the quality of accessibility evaluation of Web pages. Expert judges spent significantly less time than non-experts; rated themselves as more productive and confident than non-experts; and ranked and rated pages differently against each type of disability. Finally, both effectiveness, which is the quality of finding all and only true accessibility problems, and reliability, which is the repeatability of the outcomes when used in different context, of the expert judges are significantly higher than non-expert judges.

Mobile Web and Web Content Accessibility

2009-07-21T16:42:00.004Z

The Mobile Web Best Practices Working Group (BPWG) and the WAI Education and Outreach Working Group (EOWG) published the W3C Working Group Note: Relationship between Mobile Web Best Practices (MWBP) and Web Content Accessibility Guidelines (WCAG). Our lab member Dr. Yeliz Yesilada who is working on the RIAM project made contributions to this document and also the other related published documents.

People with disabilities using computers have similar interaction limitations as people without disabilities who are using mobile devices. This note describes the similarities and differences between the requirements Web Content Accessibility Guidelines (WCAG) and Mobile Web Best Practices 1.0 (MWBP). Following these two guidelines makes your Web content more accessible to everyone regardless of situation, environment, or device. Designing the guidelines together, instead of separately, can make the process more efficient. This note includes the following pages:

From MWBP to WCAG 1.0 and From MWBP to WCAG 2.0 are designed for those who already know MWBP and want to learn how they relate to the Web Content Accessibility Guidelines (WCAG).

From WCAG 1.0 to MWBP and From WCAG 2.0 to MWBP are designed for those who already know WCAG and want to learn how it relates to the Mobile Web Best Practices (MWBP).

Introductory information and links to related documents are in Web Content Accessibility and Mobile Web: Making a Web Site Accessible Both for People with Disabilities and for Mobile Devices.

The RIAM Project Contributes a New Extension to the W3C MobileOK Library

2009-07-21T16:39:00.002Z

The RIAM project team is happy to announce that the team have contributed a new extension to the W3C mobileOK open source library. This extension can be used to validate pages served via the file URI scheme. The W3C mobileOK open source Java library has been developed in such a way that it is very easy to extend. The RIAM team strongly encourages people to extend this library so that a better infrastructure is provided to designers for creating mobile-friendly content.

The mobileOK Basic Tests 1.0 Checker library provides a reference implementation of the tests specified in the W3C mobileOK Scheme 1.0. This scheme requires that pages are served via HTTP protocol, however there might be some cases where validating pages that are stored locally would be useful. Therefore, this new extension has been created and can be used to validate pages served via file URI scheme. The extension is designed and implemented in a way that does not affect the basic reference implementation. It is also important to note that validating pages only with this extension does not guarantee that the page is mobileOK as some tests require HTTP connection. This extension has to be used in-coordination with the W3C mobileOK Checker and does not replace the core mobileOK library.

If one wants to use this extension with the main library then they need to download and install it.

A technical documentation explains in detail how this extension can be installed and used.

This extension has been developed as part of the UK EPSRC funded RIAM (Reciprocal Interoperability of Accessible and Mobile Webs) project with the help of the Mobile Web Best Practices Checker Task Force.

IMG Seminar 22nd July 2009

2009-07-15T15:50:00.002Z

Title: A Fair License Reselling Protocol for DRM-protected Content

Presenter: Tarek Gaber

Venue: 13.00 22nd July 2009 in Mercury, Kilburn Building

Abstract:
Current DRM technologies largely focus on the copyright protection, i.e. content owners' rights. The research community has not given due attentions to consumers’ rights. In particular, these DRM technologies do not permit consumers to resell their own digital content. Meanwhile, under the first sale doctrine, it is a legitimate right for consumers to resell what they possess (e.g. digital contents). It is therefore should be allowed and protected in the DRM context. In this paper, two protocols are presented to support fair license reselling for DRM-Protected content. The first protocol is a novel fair signature exchange protocol. This protocol makes use of a concurrent signatures scheme along with a license issuer as an off-line TTP. In comparison with the related work, this protocol has the following features: (1) it reduced the workload of the TTP and (2) it is simpler to implement
The second protocol is a fair license reselling protocol for DRM-protected content. This protocol makes use the first protocol to provide fairness in the reselling process. In addition, it uses a license revocation concept to disable the reseller’s license once it is resold. The advantages of this protocol are two-fold. It does not require special devices (e.g. trusted device or smart card) to be maintained by the consumers to resell their licenses, thus making the deployment of the solution cost-effective. Additionally, there is no need for a second-hand store to be involved as an interface between the license issuer and consumers to help with the reselling process, thus reducing overhead costs.

IMG Seminar 15th July 2009

2009-07-08T13:08:00.002Z

Title: The Benefits of Semantic Structure in Peer-to-peer Networks

Presenter: Peter Weistroffer, University of Virginia

Venue: 13.00 15th July 2009 in Atlas 1, Kilburn Building

Abstract:
Peer-to-peer (P2P) technologies offer benefits in scalability, low overhead, and reduced startup costs that can be advantageous for data sharing and service discovery in the scientific community, in addition to their currently popular uses in music sharing, etc. However, current P2P systems suffer from problems such as poor search completeness guarantees, superlinear growth in message traffic, severe restrictions in allowable search queries, or a need for large centralized components. In this presentation we build on the work of Semantic Overlay Networks and show how ontologies can be used to organize hierarchical overlay networks. The combination of this structure with a simple caching scheme yields significant benefits in search efficiency and completeness, while also allowing browsing and general search queries. The additional costs per user are small and the assumptions applicable to a wide range of subjects. The second half of the talk will focus on ways to relax these assumptions and further benefits that can be gained from semantic information in the system. Last we show how this work fits into the larger goal of creating a communally organized and tagged system for sharing files and data with high usability and no large resource requirements.

IMG Seminar 8th July 2009

2009-07-06T11:06:00.002Z

Title: Adaptive Secure Routing Protocol for Mobile Ad hoc Network

Presenter: Kitisak Osathanunkul

Venue: 13.00 8th July 2009 in Atlas 1, Kilburn Building

Abstract:
In ad hoc networks, a routing algorithm is one of the most important components to perform a routing function. Each routing algorithm has its own advantages and disadvantages depending on application domains. In existing routing protocols, only one routing algorithm can be selected in order to make a routing decision. Users need to decide which algorithm is the most efficient for the intended application domain. As a result, the routing performance of the non-considered application domains is affected. The traditional routing architecture is not efficient to be applied to operate different application domains simultaneously. In addition, at the present mobile nodes are getting more capable to operate more than one application in the same network. Therefore, there is a need to develop a new routing architecture to accommodate several applications simultaneously.
We purpose an adaptive routing architecture for ad hoc networks. Our aims are to reduce the inefficient routing performance caused by using an inappropriate routing algorithm, and developing a mechanism to select an appropriate routing algorithm for operating different application domains simultaneously. In this talk, we will discuss why we need the adaptive routing architecture in ad hoc networks, what mechanism is used to select a routing architecture and lastly, how mobile nodes make routing decisions based on different routing information.